As is well known, a limb brace such as a knee brace can perform a purely prophylactic function, or provide an assistive force that helps the user to extend their limb, or both. Knee braces in particular can also provide physical protection against injury, and may for example be used by athletes involved in high-risk sports where there is a relatively high susceptibility to sustaining a knee injury.
Many individuals suffer from knee problems, often due to a prior knee injury. Some such problems can significantly affect mobility and/or the ability to support the injured person. While corrective measures such as exercise and physiotherapy, or in more serious cases surgery, can assist in correcting or partially alleviating some knee problems, there remains a need in many cases for knee support and extension augmentation.
Particularly where there has been ligament damage, for example a tear or strain in the anterior cruciate ligament (ACL), medial collateral ligament (MCL) or lateral collateral ligament (LCL), a knee brace can be used to both provide support and enhance extension strength, and thus reduce the load on the injured knee. Conventional knee braces that provide active assistance to knee extension are designed to yield when the knee is flexed, loading a torsion spring or compression spring in the process. The spring is loaded when the user bends their leg, and when extending their leg the spring unloads applying a force that augments the extension action. This also helps to support the user and prevent collapse if the injured knee buckles.
However, conventional springs do not provide sufficient force to significantly enhance knee extension or resist buckling of the knee. Furthermore, conventional tensioning mechanisms for braces do not provide an adjustable force curve allowing for precise adjustments and retention of the force curve profile over prolonged periods of usage.
It would accordingly be advantageous to provide a tensioning mechanism with an adjustable force curve allowing for precise adjustments and retention of the force curve profile over prolonged periods of usage, which provides effective enhancement of the knee extension action in cases where strength enhancement is needed and resistance to buckling of the knee.